Re: Coaxing N[] to work
- To: mathgroup at smc.vnet.net
- Subject: [mg73412] Re: Coaxing N[] to work
- From: dh <dh at metrohm.ch>
- Date: Thu, 15 Feb 2007 05:11:34 -0500 (EST)
- References: <equo6r$in0$1@smc.vnet.net>
Hi,
N can not create additional precission. You calculated lambda with
machine precission!
Daniel
p at dirac.org wrote:
> Sometimes N[,] doesn't appear to work. Like here:
>
>
> x = {2.0, 3.0, 5.0};
> A = { {6.0, 2.0, 1.0}, {2.0, 3.0, 1.0}, {1.0, 1.0, 1.0} };
> For[ k=0, k<15, ++k,
> lambda = x.A.x/(x.x);
> y = LinearSolve[A,x];
> x = y / Norm[y,Infinity];
> ]
> N[lambda, 30]
>
>
> The output is:
>
> Out[5]= 0.578933
>
> I was expecting 30 digits. Why did N[] ignore my request for 30 digits?
>